1. The Field of the Invention
This invention relates to methods for improving and enhancing the lipid layer of the tear and increasing tear breakup time by way of elevating the omega-3 index in patients suffering from symptoms of dry eye, posterior blepharitis and/or meibomian gland dysfunction and, more specifically, to methods for administering a supplementation of omega-3 fatty acids to a patient having an inflamed meibomian gland so as to facilitate an increase in the amount of omega-3's acting as an anti-inflammatory and, respectively, decrease the amount of omega-6's acting as an inflammatory in the meibum composition, thereby normalizing the lipid layer of the tear and effectively reducing or eliminating the symptoms of dry eye, posterior blepharitis and/or meibomian gland dysfunction.
2. The Background Art
Dry eye is a condition in which there are insufficient tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. People with dry eyes either do not produce enough tears or have a poor quality of tears. With each blink of the eyelids, tears are spread across the cornea in order to provide lubrication, to wash away any foreign matter and to keep the surface of the eyes smooth and clear.
Tears are produced by several glands in and around the eyelids. When the normal amount of tear production decreases or tears evaporate too quickly from the corneal surface, symptoms of dry eye can develop.
As appreciated, tears are made up of oil, water and mucus. Each component serves a specified function in protecting and nourishing the front surface of the eye. A smooth oil layer helps to prevent evaporation of the water layer, while the mucin layer functions in spreading the tears evenly over the surface of the eye. If the tears evaporate too quickly or do not spread evenly over the cornea as a result of deficiencies with any of the three tear layers, symptoms of dry eye or posterior blepharitis may ensue.
Along the margin of the eyelids are a series of small sebaceous glands called meibomian glands. The meibomian glands create and distribute a supply of meibum, an oily substance, that makes up the lipid layer of the tear. The supply of meibum functions to help keep the eye moist and tends to protect the tear film from evaporation. There are approximately twenty-five meibomian glands on the upper eyelids and twenty-five meibomian glands on the lower eyelids. Upon blinking of the eye, the upper eyelid comes down, presses on the oily substance produced by the meibomian glands, and pulls a sheet of this oily substance upwards, thereby coating the tear layer beneath to keep it from evaporating. This oily substance or meibum (wherein lipids are a major component) which is created by the meibomian glands is therefore critical for healthy eyes and clear vision.
Meibomianitis refers to inflammation or dysfunction of the meibomian glands which is also referred to in the art as meibomian gland dysfunction. Inflammation of the meibomian glands may occur because of the production of meibum which is pro-inflammatory in nature as a result of an increased composition of omega-6 essential fatty acids. Secondarily, bacteria have been found to invade the meibomian glands and colonize there. Once inflamed, the meibomian glands generally will not function in a manner sufficient to adequately produce the quantity and quality of oils necessary to properly lubricate the eye.
The volume of oil produced from inflamed meibomian glands tends to decrease and the oils that are produced become thicker in composition, like toothpaste. These oils also become abnormal in their characteristics. Instead of spreading evenly across the aqueous layer, the oil coalesces leaving areas on the corneal surface in which the aqueous can evaporate and other areas in which the oil adheres to the cornea surface itself. This creates a dry spot on the cornea for which the aqueous cannot penetrate. Such condition generally produces a foreign body sensation and if it persists may result in injury to the epithelium which is seen as corneal staining on examination. A reduction in oil production therefore inherently results in a quantitative decrease in the quality and quantity of the oily layer, thus causing tears to evaporate more rapidly. Because the thickened oil does not coat the eye properly, a person with inflamed meibomian glands may experience discomfort or problems with their eyes that may include, for example, but not by way of limitation: (1) dryness; (2) burning; (3) itching; (4) irritation and redness; (5) blurred vision; and/or (6) foreign body sensations.
This inflammatory process can also spread throughout the lid margin and spill over to involve the ocular surface resulting in significant ocular discomfort. Inflammation of the meibomian glands in the upper and lower lids can further lead to vascularization and fibrosis, causing stenosis and then closure of the meibomian gland orifices. Deprived of the meibum or lipids that inhibit evaporation, tear film evaporation will generally increase. Similarly, a deficiency in tear film generally results in irritation of the eye, but can also cause damage to the surface of the eye. As appreciated, an irregular oil pattern disrupts tears and allows for increased exposure of the aqueous layer to the atmosphere and the increased evaporation of the aqueous. Unfortunately, this inflamed condition of the meibomian glands has often been found to be chronic.
Some of the treatments for meibomianitis that have been contemplated by those skilled in the art include: (1) the application of artificial tears; (2) cleaning the affected eyelid margins with a gentle baby shampoo; and (3) applying warm and moist compresses 5-10 minutes two to three times per day in an effort to promote normal eyelid glandular function. A physician may also prescribe a topical and/or oral antibiotic such as, for example, tetracycline, erythromycin, or doxycycline, to help eradicate the bacteria found in the glands and to facilitate a breakdown in the thickened lipid secretions from the meibomian glands. These various treatments, however, can often take months before a treated patient notices any significant improvement. Although the elimination of bacteria or anti-inflammatory effects of the antibiotics resulted in a temporary change, none of the known treatment methodologies have brought long-lasting relief to patients. Hoping to provide a form of sustainable relief to the ongoing symptoms associated with dry eye, with or without meibomian gland dysfunction, that are suffered by patients, a study was conducted by those skilled in the art to investigate the effects of dietary supplementation of a combination of flaxseed and fish oils on the tear film and the ocular surface. At the baseline, all patients in the study had a history of dry eye or one or more symptoms of posterior blepharitis. At the end of the study, the clinical results did not achieve any statistical significance, wherein the lipid composition of the samples collected from the omega-3 supplemented group was found to be very similar to that collected from the placebo group. Thus, the study concluded that dietary supplementation of flaxseed oil and omega-3 fatty acids for treating dry eye or meibomianitis showed no significant effect on meibum composition or aqueous tear evaporation rate.
Consistent with the foregoing, in order to control or resolve the long term effects of dry eye, posterior blepharitis, or meibomian gland dysfunction, the characteristics or nature of the oil (meibum) that is produced by the meibomian glands must be normalized. Thus, what is needed are nutritional or dietary supplement compositions and treatment methodologies using the same that effectively change the quality of the meibum composition, thereby resulting in a meibum composition having a direct correlation to enhancing and improving the function and/or composition of the lipid layer of the tear which reduces the symptoms associated with dry eye, posterior blepharitis and/or meibomian gland dysfunction.